This is their 17th year doing the survey and compiling the Top 50 — a list created from more than 200 questions on female representation at all levels, and extensive analysis of company programs and policies.

Business Insider spoke with the vice president and general manager of NAFE, Subha Barry, about the findings. "Being on this list says a couple of things about a company," says Barry. "They not only support women advancement and development, but they recognize that women constantly need to do more. These companies are always striving to do better. They're the ones continually doing innovative things."

Survey highlights include:

Women make up 40% of the top 10% of earners in the NAFE Top 50, which is the highest percentage ever and grew from 35% in 2014.

Among the NAFE Top 50, 29% of board of directors members are women, compared with 19% across the S&P 500.

Half of the NAFE Top 50 companies now have four or more women serving on their board of directors.

Among the NAFE Top 50, 10% of the CEOs are female, compared with 5% across the S&P 500.

Procter & Gamble and Prudential Financial have both earned a spot on the list for 15 years, and they were honored as the new hall of famers this year.

National Association for Female Executives

"What was surprising was the growth in top earners from 35% to 40%," says Barry. "That's a pretty big leap. The other surprise was that the percentage of board seats held by women improved from 27% to 29%; and more than that, half of the top 50 companies have four or more women serving on the board."